Python Versions Used in Commercial Projects in 2017

Out of all programming communities, Python's is the fastest growing one.
Same as previous year, we'll take the opportunity to check which Python versions
are used for building real-world applications on Semaphore's hosted CI service.

Last year's report received a lot of attention on Hacker News
and various forums because it showed that
over 70% of people were still using Python 2.7 at work. This year, results are a bit better for Python 3.

In 2017, 63.7% of people use Python 2.7., which is 8.2% less than last year.

The final version of 3.0 was released in December 2008, and, although it was
expected that most of the community would upgrade, that still hasn't
happened. Python 2.7 was released 7 years ago in July 2010, and the end date for
long-term support (LTS) maintenance period has not yet been decided, since the
majority of projects are still using it. "If it ain't broke, don't fix it" seems
to be the favorite proverb of the Python community.

The data also shows that the teams that opted for Python 3 find it easier to adopt
newer versions. Last year, 60% of them used version 3.5 and 39% used 3.4. This
year, the majority (43%) still uses version 3.5, followed by 35% of projects
using version 3.6. The number of projects running Python 3.4 has dropped by 20%.

As of April this year, AWS Lambda supports both Python 3.6 and 2.7.
Semaphore's platform
also supports a wide range of Python versions: 2.6.9, 2.7.10, 3.3.6, 3.4.3,
3.5.0, and 3.6.0.

As you can see, changes in the Python 3 community are happening fast, and it's
gradually becoming more granulated.

Next year, we'll follow up on this report to see how the Python community is
dealing with future updates.

How do you approach choosing the Python version at work? Let us know in the
comments below.